A normal rat ovarian cell line has been established which produces steroid hormones. It can grow idefinitely in a defined medium in which the serum is replaced by insulin, transferrin, hydrocortisone and triiodothyronine. To attempt to understand the mechanism of action of the hormones, the effect of hormone deficiency on the traverse of cells through the cell cycle will be studied. We will transform the ovarian cells with oncogenic viruses and carcinogens and see how their hormonal requirements change. Normal adrenocortical cells from rats have been established in culture. Their hormonal requirements for growth in the absence of serum will be determined. Growth factors from blood meal will be isolated.